Ergonomic and workload assessment in weeding operation conducted for wheat crop for male respondents

The present findings focuses on the assessment of anthropometrical, physical and physiological characteristics undergone by male operators during weeding operation. The variations were measured prior to and after the commencement of weeding activity. The VO2max and AWL was 27.59 mL/Kg min and 9.61 respectively.

Original Research Article https://doi.org/10.20546/ijcmas.2019.809.301

Ergonomic and Workload Assessment in Weeding Operation Conducted

for Wheat Crop for Male Respondents

Vishnu Ji Awasthi 1* , Manpreet Singh 2 , RajatMishra 3 , Rahul Chaudhary 1 ,

Mirtunjay Pandey 4 , Dilwar Singh Parihar 5 , Shubham Gautam 6 and Dhiraj Kumar 7

1

Farm Machinery and Power Engineering, VIEAT, Sam Higginbottom University of

Agriculture, Technology and Sciences, Prayagraj-211 007, UP, India

2

Farm Power and Machinery, Department of Farm Machinery and Power Engineering,

Punjab Agricultural University, Ludhiana-141 004, Punjab, India

3

Soil and Water Conservation Engineering, VSIAT, Sam Higginbottom University of

Agriculture, Technology and Sciences, Prayagraj-211 007, UP, India

4

Farm Machinery and Power Engineering, Faculty of Agricultural Engineering, Bidhan Chandra KrishiVishwavidyalaya, Mohanpur, Nadia-741252, West Bengal, India

5

Farm Machinery and Power Engineering, CAE, Jawaharlal Nehru KrishiVishwaVidyala,

Jabalpur- 482 004, MP, India

6

Renewable Energy Engineering, VSIAT, Sam Higginbottom University of Agriculture,

Technology and Sciences, Prayagraj-211 007, UP, India

7

Soil and Water Conservation Engineering, IAS, Banaras Hindu University, Varanasi- 221

005, UP, India

*Corresponding author

A B S T R A C T

International Journal of Current Microbiology and Applied Sciences

ISSN: 2319-7706 Volume 8 Number 09 (2019)

Journal homepage: http://www.ijcmas.com

The present findings focuses on the assessment of anthropometrical, physical and physiological characteristics undergone by male operators during weeding operation The variations were measured prior to and after the commencement of weeding activity The VO2max and AWL was 27.59 mL/Kg min and 9.61 respectively Assessment of physiological parameters includes average resting heart rate of the respondents which was reckoned as101.33 bpm The average working heart rate during weeding activity in case of hand hoe and wheel hoe was 112.33 and 108.83 (bpm) respectively The average EER and OCR values were 8.19 kJ/min and 0.53 L/min in case

of hand hoe and for wheel hoe it was 7.88 kJ/min and 0.51 L/min respectively The average BPDS of subjects were ascertained as 25.4and 21.4 for hand hoe and wheel hoe respectively The subjects experienced light physical work in case of wheel hoe and moderately heavy physical work in hand hoe

K e y w o r d s

Physiological

variations,

anthropometric

dimensions,

VO2max

Accepted:

24 August 2019

Available Online:

10 September 2019

Article Info

Introduction

Agriculture offers the basic means of income

for majority of Indian farmers The workers

use various types of tools, equipment’s and

machinery for their day to day activities in the

agricultural fields Use of proper tools

provides effective and sonorous results and

hence it becomes utmost necessary to consider

the human factor in the design of farm tools to

enhance the operating efficiencies, working

comfort and thereby improving the

productivity of workers Ergonomically

designed equipment’s/tools enhance the

human operating efficiencies and comfort

during its operation The ergonomics being the

branch of science is applied in every of field

since it involves the aspects of man, machine

and working environment It, therefore plays a

vital role in every workplace with the factor

mainly focussing on the level of ease and

safety to the subjects performing the desired

operation in a particular work layout Every

field of science is somehow interconnected

with the prospects of ergonomics and its

related extent Agriculture is also closely

related to it since it constitutes a way to bring

man (operator), machine (implement) and

working environment (field) It is an

imperative measure of operator’s performance

in carrying out any agricultural operation It is

regarded as the application of anatomical,

physiological and psychological knowledge in

the man, machine and environment The

workers use various types of tools,

equipment’s and machinery for their day to

day activities in the agricultural fields Use of

proper tools provides promising and

encouraging results and hence it becomes

utmost necessary to consider the human factor

in the design of farm tools to enhance the

operating efficiencies, working comfort and

thereby improving the productivity of

workers In keeping a view of this, the concern

research deals with the ergonomic evaluation

of male operators in weeding operation which

is performed by hand hoe (khurpa) and the wheel hoe The performance of a weeder not only depends on the constructional features but also on the workers operating them The performance of man-implement system may

be poor, if ergonomics aspects are not given

due attention Tewari et al., (1991) stated that

the performance of the weeder is interpreted in terms of weeding efficiency and the grade of work relates to rating of workload while worker’ comfort is the subjective assessment

of operating posture The physiological cost of work includes the heart rate (HR), oxygen consumption rate (OCR) and energy expenditure rate (EER) Ease of performing an operation affects the output of the worker

Ergonomic evaluation is a tool to evaluate the energy expenditure of work, their physiological cost and suitability of the method for farm workers and how long they can work continue without getting fatigue

(Kumar A et al.,2013) Hence, to address

these concerns of ergonomics in the field of agriculture to provide safe and comfort to the farmers and operators, the major thrust of the research findings is to assess the physical and physiological responses resulting in addition

to the anthropometric dimensions and body part discomfort for the operators engaged in the farm operation

Materials and Methods

The study was conducted at Agricultural farms, Department of Farm Machinery & Power Engineering, Vaugh Institute of Agricultural Engineering and Technology, Sam Higginbottom University of Agriculture, Science and Technology, Prayagraj (Allahabad)

The details of materials, procedures followed, and techniques adopted during the course of present investigation have been elaborated in this chapter under the following headings

Experimental setup

Equipment employed for weeding activity

which are taken into consideration

Hand hoe

Hand hoe used in weeding operation is

khurpa It is traditional weeding and

inter-culture tool It essentially consists of a blade

attached to a ferrule The blade is used to

uproot the weeds It consists of a wooden

handle to manipulate it according to its

necessity It is usually operated by the rural

labours to perform the weeding operation The

work rate of hand hoe is about 0.01ha/hr

Wheel hoe

It is a manually operated weeder mostly used

by both male and female operators owing to

its high work rate of 0.05ha/h It consists of a

single sharp tyne blade and a single wheel to

move hoe to a desired direction It is operated

in a standing posture which renders the

operator more mobile

Method – (In order to implement the

experimental plan)

The ergonomic study was conducted in

Agricultural farms, SHUATS, Prayagraj and

its nearby villages The anthropometric data of

the selected operators was measured during

the study Weeding operation was carried out

by hand hoe i.e khurpa and wheel hoe at the

desired site prescribed in the field of wheat

crop with row to row spacing 0.95m

Sixty male respondents in the age group of 25

to 50 years (i.e 20-25, 25-30, 30-35, 35-40,

40-45 and 45-50) were selected The

mentioned age interval comprises 10

respondents The operators were chosen at

random to perform weeding operation by hand

hoe and wheel hoe Different replications (3

replications) were taken for the subjects during their performance by the listed hoes These replications are performed on different days and each trial by each subject for each implement was 30min duration

The subjects were selected on the basis of range of various age to conduct the evaluation

of the performance from ergonomic point of view

The past history of the respondents was considered with the intent to obtain the sonorous results in the present research study The subject was made well acquainted with the experimental protocol to achieve their full co-operation and to maintain the uniformity in the measurement Proper co-ordination and a sort of collaboration was achieved with the subject

Firstly, all the anthropometric measurement is taken including height, weight and other body parameters of different ages of the subject After words they were allowed to perform the weeding operation by employing the mentioned hoes for a duration of 20min Before the commencement of the weeding operation

The physiological parameters of the subject were taken such as heart rate (maximum and minimum) heart rate and resting and working blood pressure (both Systolic and Diastolic) were measured at one-minute intervals after five minutes from the beginning of work After that, other variables whose values depends on above enlisted parameters including OCR, EER and CCW were calculated

The same procedure was repeated to get three sets of trials or replications and the average of the three sets was used to achieve the rigorous readings

Physical, physiological and discomfort

parameters involved in the concern study

for the male subjects

BMI

The BMI is defined as the body mass divided

by the square of the body height The relation

of BMI is given as:

BMI = Weight/ (Height)² -2.1

LBM

Lean body mass is a component of body

composition, calculated by subtracting body

fat weight from total body weight

(0.33929*H)- 29.5336 -2.2

Estimation - LBM is usually estimated using

the relation given by Hume, R (jul 1966)

Weight

The quantity of matter contained by the body

is weight Body weight of male and female

subjects (in Kg) of different ages is measured

by employing calibrated weighing scale

Stature

Stature is the vertical distance (in cm) from

the standing surface to the vertex of the head

when the subject stands erect and looks

straight forward

BMR

Basal Metabolic Rate is the number of calories

required to keep your body functioning at rest,

also known as the metabolism It is related to

body mass, age, weight and height It is also

affected by gender By Harris Benedict

Equations,

BMR for male operators is represented by the following equations:

For men - BMR= 66.47 + (13.7 x Weight) + (5 x Height) - (6.8 x Age)-2.3

VO2max

Also known as maximal oxygen consumption, maximal oxygen uptake, peak oxygen uptake

or maximal aerobic capacity It is the maximum rate of O2 consumption measured during any physical operation (here implies to the weeding operation) The name is derived from V- volume, O2- oxygen and max- maximum.VO2max is expressed in litres of oxygen per minute (L/min) It can also be expressed in mL/kg min

VO2max is determined in the research study

by utilizing the Uth- Sorensen- Overgaard- Pedersen estimation, the equation is based on maximum and resting heart rates and proposed

by a group of researchers from Denmark It is given by:

VO2max ≈ (HRmax / HRrest) x 15.3 mL/kg minute -2.4

This equation for VO2max is applicable only for the subjects having age between21 to51 only and it lies within the range of age taken

in the present findings

AWL

AWL stands for acceptable work load It is equal to 35% of the VO2max of the subjects (for young Indian worker)

Maximum heart rate

In the concerned research, it was determined

by utilizing the formula derived by Maritz et

al., (1961)

HRm= 220 ̶ Age (years)-2.5

Energy Expenditure Rate (EER)

EER is determined and estimated using the

following formula proposed by Verghese et

al., (1944) in studying the EER of the workers

EER = 0.159 X Average heart rate - 8.72

(KJ/min) -2.6

Oxygen Consumption Rate (OCR)

Computed from the heart rate values

(previously measured of the operator subject

OCR is represented by the equation (Singh et

al., 2008) enumerated as follows:

OCR (L/min) = 0.0114 X HR - 0.68 -2.7

Cardiac cost of work (CCW)

CCW is determined by employing the

following relation: CCW = AHR * Duration

of activity AHR = Average Heart Rate

(beats/min) Duration of activity = 30minutes

(weeding activity was performed for duration

of 30min in the present study work)

AHR = Average working heart rate - Average

resting heart rate

CCW = AHR x Duration of activity -2.8

Body part discomfort score (BPDS)

Corlett and Bishop (1976) technique was used

to measure confined discomfort In this

method, the body of respondents is divided

into 27 regions Each body region was

numbered differently to avoid a subject

marking on body region only The subject was

asked to mention to all body parts with

discomfort, starting with the most painful, the

next painful in descending order till no further

areas are referred In the present research, it

was examined by proper investigating the level of fatigue for the selected subjects and

by means of relation enumerated below (Corlett and Bishop, 1976):

where, Xi= number of body parts and S= discomfort score (6 to 1)

In the current research findings, the atmospheric conditions including average temperature, humidity and amount of sunshine was also assessed during the replications of the method taken in the month of February and March (as shown in the table 2.4)

The anthropometric data of the selected respondents was ascertained The dimensions were measured by deploying anthropometer and measuring tape to maintain accuracy and preciseness in the results Sixteen anthropometric measurements were taken, which were considered useful in utilizing the aforementioned tools The corresponding strength data is enumerated in the table 2.5 given below:

Statistical analysis employed

The statistical analysis was considered to check the significant variation in the measured values with respect to ages of the respondents The three replications were taken, and the values of average heart rate were deliberately examined by constructing the ANOVA in order to check the significance difference in the values with the mentioned ages Split-plot design was employed during the research study The coefficient of variance for the selected respondents was found to be 2.21 Since, the calculated variance ratio was slightly higher than its tabulated value, the alternative hypothesis was accepted which indicate that there is a significant variation in the working heart rate with different ages

Results and Discussion

The results obtained from the present

investigation has been summarized in this

chapter The factors taken under consideration

in this concern research study are analysed

and the inferences has been drawn pertinent to

various physical and physiological parameters

The study focuses on its objectives by

producing the results and its concise

discussions are enumerated under following

heads:

Regarding assessment of physical properties

of male subjects

The BMI values calculated for the subject of

ages 25, 30,35,40,45 and 50 were found as

19.86, 19.36, 20.29, 21.43, 19.33 and 21.95

respectively The average value of BMI for the

subjects of given ages were 20.37kg/m² The

average value calculated was found normal

and lies between the standard values

18.5-25(WHO 2006)

The average LBM value of the selected

respondents was found to be 43.22 for

different ages 25-50 years The calculated

value of LBM of various enumerated ages

were 45.87, 40.49, 45.16, 44.47, 41.86, 41.45

and 43.22 respectively

The values pertaining to BMR for the subjects

of aforesaid ages were calculated and were

found to be 1477.57, 1328.77, 1425.67,

1390.37, 1238.07 and 1251.27 respectively

The average value calculated for the subjects

was 1351.95

The VO2max values of the respondents lies

between the range 26-29 mL/Kg min (as

indicated in the table 3.1) The lower values of

VO2max of male subjects were

encountered(VO2max< 38 for men of ages

between 20-29 is considered low – Astrand-

1960)

The acceptable work load for Indian worker is about 35% of VO2max Hence, for the mentioned values of VO2max, the AWL of male respondents having age 25,30,35,40,45 and 50 were 9.76, 9.86, 9.97, 9.80, 8.95 and 9.3 respectively

Regarding assessment of physiological parameters of the respondents

The average resting heart rate of the male respondents of age 25, 30,35,40,45 and 50 was found to be 104, 101, 98, 95,105 and 99 respectively Therefore, the average value of resting heart rate of the subjects was 100.33 bpm before carrying out the operation(weeding) by hand hoe In case of wheel hoe, it was 100.5 bpm as illustrated in

the table 3.2

Reason for the increase in resting heart rate for wheel hoe

An approximate increase in the average resting heart rate for wheel hoe might be due

to initial weeding activity carried out by hand hoe for 20 minutes duration and then the subjects were allowed to take the required rest

so that they could proceed for operation by wheel hoe

This might be the reason for the enhancement

of the resting heart rate when operation was conducted by wheel hoe

The average working heart rate was measured for the respondents during accomplishment of work after 20 minutes duration During the weeding operation conducted by hand hoe, the values of average working heart rate of male respondents of ages 25, 30, 35, 40, 45 and 50 were recorded as 116, 111, 110, 108, 119, and 110(bpm) respectively and 115, 107, 109, 104,

111 and 104(bpm) respectively in case of weeding activity performed by wheel hoe

Comparison of average working heart rate

for weeding operation conducted by hand

and wheel hoe

The mean value calculated of average working

heart rate for male subjects sustaining weeding

activity by hand hoe and wheel hoe was

112.33 and 108.33(bpm) respectively

By estimating the average heart rate value, the

EER was calculated which is represented by

the equation 3.6 For male respondents of the

mentioned ages, the EER values when task

was conducted by hand hoe were 8.77, 8.13,

7.82, 7.42, 9.09, 7.40 and8.19 (kJ/ min)

respectively While the EER values calculated

for wheel hoe were 8.83,7.74, 7.58, 7.18, 8.61

and 7.34 (kJ/ min) respectively Therefore, the

average value of EER for male subjects during

weeding operation conducted by hand and

wheel hoe were 8.19 and 7.88 (kJ/ min)

respectively

The values of OCR were calculated as 0.57,

0.53, 0.51, 0.48, 0.60, 0.51 and 0.53 (L/ min)

respectively when the subject accomplishes

the weeding activity for the given duration of

20 minutes by hand hoe However, in case of

activity conducted by wheel hoe for the same

subject of the above enlisting age, the readings

were calculated as 0.58, 0.50, 0.49, 0.46, 0.56

and 0.47 (L/ min) respectively The average

OCR was 0.53 and 0.41 (L/ min) for hand hoe

and wheel hoe respectively The OCR was

slightly enhanced when the subjects carried

out the work by hand hoe than by wheel hoe

The CCW values, when task was conducted

by hand hoe were 240, 200, 240, 260, 280 and

220 (beats) respectively for the enumerated

ages While the CCW values calculated for

wheel hoe were 180, 140, 260, 160, 80, and

120 (beats) respectively Therefore, the

average value of CCW of the respondents

during weeding operation conducted by hand

and wheel hoe were 240 and 156.67 (beats)

respectively The cardiac cost of work was

maximum when the subjects carried out the work by hand hoe rather than by wheel hoe Similar results were observed in the study

conducted by Verma S et al., (2011) The

average BPDS values of selected subjects were ascertained as 25.4and 21.4 for hand hoe and wheel hoe respectively as enumerated in the table Similar results were investigated by Kumar et al., 2002 The majority of body discomfort experienced were fatigue in knee and shoulder while it was arm, knee, wrist and shoulder in case of weeding operation conducted by hand hoe owing to the large effort required by the arms to uproot the weeds However, for wheel hoe, the subjects undergoes lassitude which might be due to the high temperature of the surrounding ambience

It was investigated that wheel hoe was efficiently designed and its sharp tynes offers little effort to remove the weeds Thereby, it is concluded that wheel hoe offers easy adaptability and consistency in accomplishing the weeding activity in standing posture rather than the difficulty in manipulating the hand hoe in squatting position

properties of male subjects

From the estimated values of LBM, the percentage of LBM in the body weights for male subjects of ages 25, 30, 35, 40, 45 and 50 was found to be 78%, 83%,81%, 78% 81% and 77%.The percentage of male subjects lies above 75%.So, it may be concluded that all male subjects of given ages were physically fit and healthy for performing the farm operation They have perfect values of average LBM (as stated by National Academy of Sports Medicine 2006)

Reason for the declination of VO2max in male

subjects – Consumption of alcohol, smoking

and chewing of tobacco might be the reason for the declination of VO2max Cardiac

efficiency is reduced as the VO2max declines

Smoking reduces work capacity by reducing

the oxygen carrying capacity of the blood

Before the research study, the past history of

the respondents was taken into consideration

Above all, it is concluded that VO2max declines as the age progresses Also in the presented findings, the average value of VO2max of male respondents was found to be 30.16mL/Kg min

Table.1 The concise outlook of the experimental plan is enumerated in the mentioned table

Brief outlook of the experimental plan

Farm operation Weeding

Implements used Hand hoe and wheel hoe

Total number of operators 60

Total number of replications 3

Duration of weeding activity 30 min

Table.2 Enlistment of materials requirement for implementing the experimental plan

1 Anthropometric

dimensions

For measurement of small and large body dimensions

Anthropometer, steel scale, measuring tape

2 Physical

variables

3 Physiological

responses

Pulse rate Electronic sphygmomanometer,

pulse oximeter

Implements for carrying out weeding operation- Hand hoe (khurpi) and Wheel hoe

Table.3 illustrating the features of weeding implements

Specifications and working features of the mentioned weeding implements

1 Overall length (mm) 320 Overall length (mm) 1680

2 Width of cutting edge (mm) 120 Width of cutting edge (mm) 110-180

3 Length of the blade (mm) 220 Length of the blade (mm) 150

Table.4 Enumeration of operating conditions

1 Average temperature, 0C 34

2 Average humidity, % 52

3 Average sunshine, hours 8.4

Table.5 The anthropometric data of the male respondents

data

Age of male operators

25 30 35 40 45 50

(Measurement taken in cm unless otherwise specified)

Table.6 Depicting the physical characteristics of the selected respondents

S.no Physical

characteristics

(mL/Kg.min)

31.82 32.34 34.05 29.45 27.97 25.3 30.16

Table.7 The assessment of physiological responses f the male respondents conducting weeding

operation by hand hoe and wheel hoe

Ⅰ By hand hoe (khurpa)

Ⅱ By wheel hoe

Table.8 Assessment of average BPDS of the female operators in various farm operations

S

No

1 Weeding by hand hoe 23.50 23.90 24.75 25.65 26.85 28.70 25.4

2 Weeding by wheel hoe 20.25 20.90 21.15 21.75 22.35 22.50 21.4